The Michigan Department of Environment, Great Lakes, and Energy (EGLE) testing has not detected the presence of hexavalent chromium in the Huron River system downstream after the chemical release.
According to MDHHS, EGLE crews tested 55 locations throughout the river system from Barton Pond on Aug. 6, where the city of Ann Arbor has a drinking water intake upstream to Wixom. None of the 75 samples tested from those locations had detectable level of either hexavalent chromium or total chromium, reported EGLE.
Testing followed the discharge of industrial chemicals to the sanitary sewer system from Tribar Manufacturing in Wixom the weekend of July 30, which were then routed to the Wixom wastewater treatment facility which discharges to Norton Creek and then flows into the Huron River system. The liquid contained hexavalent chromium, a known carcinogen.
Of 144 water samples collected throughout 42 river miles since the release, three came back with detections of hexavalent chromium, reported MDHHS. Two detections were collected in Milford’s Hubbell Pond and one in the middle of Kent Lake. The Kent Lake detection was 5 parts per billion (ppb). The two Hubbell Pond detections were 11 and 9 ppb and all three were at or below values to protect aquatic life.
Investigators are evaluating test results from wastewater solids sequestered at the Wixom Wastewater treatment plant that may have trapped chromium, as well as a carbon filtration system at Tribar that may have trapped the hexavalent chromium before it was discharged to the wastewater plant, reported MDHHS.
MDHHS is "recommending that people and pets avoid contact with the Huron River water between North Wixom Road in Oakland County and Kensington Road in Livingston County. This includes Norton Creek downstream of the Wixom Wastewater Treatment Plant (Oakland County), Hubbell Pond (also known as Mill Pond in Oakland County) and Kent Lake (Oakland and Livingston counties)."
However, officials add that properly constructed and permitted drinking water wells should not be directly influenced by surface water and are unlikely to be contaminated by any chromium in the river.
"Unpermitted driven sand points and submerged irrigation pumps installed by property owners along the river may be vulnerable and should never be used for drinking water," notes MDHHS.
EGLE staff will also continue the investigation to determine why the release occurred, the exact volume and product released, and the timeline.
